Preoperative considerations with extended depth-of-focus lenses

A healthy ocular surface is important for success with any refractive IOL, so it is a good idea to set the stage months (if not years) before cataract surgery by counseling patients about therapy and prevention as soon as there are early signs of ocular surface disease.

During initial consultation, I emphasize that early treatment can make a difference in their future vision after cataract surgery, including which lenses they are candidates for. With patients who have dry eye, I often repeat biometry multiple times before surgery, especially if there are discrepancies in the keratometry or other measurements.

EDOF lenses are more forgiving of residual refractive error, but it is still important to be meticulous about preoperative measurements and management of astigmatism. Compare topography and tomography to make sure that any astigmatism is regular and relatively consistent, and obtain optical coherence tomography imaging to help identify any macular pathology.

I also watch for subtle conditions, such as Fuchs’ dystrophy, anterior basement membrane dystrophy, and amblyopia, and perform a pinhole near-vision test to ensure that there are no non-refractive issues that could affect visual outcomes.

My A-constant for the Symfony lens is 119.35, very similar to that of another lens (Tecnis monofocal, Johnson & Johnson Vision).

For power calculation, I prefer the Barrett Universal Formula or the Barrett Toric Calculator, which helps ensure that posterior corneal astigmatism is taken into account. I also perform intraoperative aberrometry on most of my patients.

I always test for eye dominance, because I prefer to operate on the dominant eye first and try to maximize distance vision in that eye. I like to center the IOL on the patient-fixated coaxially sighted corneal light reflex but it is also comforting to know that clinical studies have shown that these lenses perform well with up to 0.75 D of decentration.

That means we do not have to be as concerned about eyes with higher angle kappa.

I recommend waiting a few weeks after implanting your first EDOF lenses to evaluate the initial outcomes. In my early cases, the day 1 outcomes were slightly myopic, which at first led me to believe my power calculations might be off. However, I found that patients settled toward emmetropia within 2 weeks.

As with any other premium lens, patient counseling and good measurements are critical to good outcomes with EDOF lenses. In order to really embrace this technology, it is important to have a good early experience, so choose your cases wisely and invest the time to take a careful approach preoperatively.

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